。
She received nothing in return for her kindness.
Literal
She [topic-は] kindness [possessive-の] compensation [as-として] nothing [object-を] did-not-receive.
代償 (だいしょう) means 'compensation, price, recompense' — it frames kindness as something that could have been exchanged for reward. The pattern ~として marks it as the role or frame: 'as compensation for.' 何も~なかった is the standard pattern where 何も ('nothing at all') requires a negative predicate, producing 'did not receive anything.'